TaCkY.
I have never received a formal invitation with registry info or directions to give $ for a honeymoon. I would find that odd today still! I've gotten maybe 2 baby shower invites with registry info, but even that is still very rare to me.
With social media accounts and wedding websites, there is no reason to tacky up the beautiful formal invitation mailing with stuff about Target, Macy's or a venmo/travel fund. That info can be displayed elsewhere and found easily in many public social sites. I just cannot imagine myself saying "venmo me" when inviting you to celebrate a marriage.
Still, also with social media and blogs, you see other people doing this stuff easy breezy..... so maybe you start to think it is the new normal.
I'd take a deep breath, mutter "kids these days" and move on. I do get why it'd be "shocking" to someone even a generation older than I. My mom is fairly hip to the tech, but I am doubt she would even know what venmo is!